1. Field of the Invention
The present invention relates to an exposure apparatus and a device manufacturing method.
2. Description of the Related Art
A liquid immersion exposure apparatus is known as an exposure apparatus having a high resolution. The liquid immersion exposure apparatus fills a liquid between a final surface of a projection optical system and a substrate, and projects a pattern of an original on the substrate via the projection optical system and the liquid to expose the substrate. In the liquid immersion exposure apparatus, in a case that a bubble exists in the liquid between the final surface and the substrate, the bubble shields and refracts the exposure light, causing a reduction in a resolution of the pattern. Therefore, the liquid immersion exposure apparatus uses liquid that has undergone deaeration processing. Further, in this liquid immersion exposure apparatus, an auxiliary member is provided on a peripheral part of the substrate and a measuring plate, in order to suppress liquid leakage during the exposure in a peripheral edge of the substrate and during measurements such as focus and alignment. Japanese Patent Application Laid-Open No. 2011-109092 discloses a sealing member that is provided for suppressing liquid leakage into a gap between the auxiliary member and the measuring plate, and has a polymer sealing part and an adhesive layer.
However, the sealing member as described above has a micro gap while contacting with the measuring plate and the auxiliary member. While water-repellency is controlled on the surface of the members such as the measuring plate, the sealing member, and the auxiliary member with which immersion liquid is in contact, gas exists in the micro gap. Therefore, when liquid that has undergone deaeration processing is placed on the sealing member during the measurement at the measuring plate and the like, the liquid dissolves air in the micro gap. When the gas in the micro gap of the sealing member dissolves in the liquid, the gap acquires a negative pressure and the liquid enters the micro gap. Because the liquid that has entered the micro gap stagnates in the micro gap with a force stronger than holding force of the immersion liquid, the liquid may remain in the micro gap, even after the measurement at the measuring plate and the like is completed and immersion liquid moves. Moreover, the immersion liquid is partially drawn by the liquid in the micro gap and the large liquid residue may occur. In particular, in the case where a cross-sectional structure having the micro gap forms a closed space and the liquid covers all of the closed space and in the case where intermolecular forces generated by the liquid that has entered the micro gap is stronger than surface tension of the liquid, liquid film residue covering all of the closed space occurs. The liquid residue causes the reduction of the exposure accuracy on the substrate and the liquid residue pollutes the measuring plate upon drying on the measuring plate, thereby causing the measurement fault.